1. Field of the Invention
The present invention relates to a microfilm reader/printer for reading and printing an image selected from image information recorded by the duo mode in the upper and lower channels on a microfilm.
2. Prior Art
As one of the photographic techniques, the duo photograph method (reciprocal photographing method) has been adopted, in which images are recorded successively in respective frames in one channel on one-half of the film width during one passage of a microfilm roll, then the microfilm is loaded in the upside down condition to record images in the other channel on the unused half of the film width. In one conventional microfilm reader/printer for reading a microfilm on which images are recorded by the duo photographing mode (such a film will be referred to as "duo mode microfilm" in the following description), transportation of film is automatically stopped after the completion of retrieval along one channel to indicate that the operator must exchange the channel to be retrieved and turn the images to be printed to the inverted orientation. In another known microfilm reader/printer, only one channel is read so that the microfilm roll is once rewound and removed from the reader/printer and then reloaded by the operator while being turned in the inverted condition every time when retrieval through one channel is completed. Such operations are cumbersome and time-consuming.
In reading and printing images recorded on a duo mode microfilm, since the orientation of images in one channel is in the inverted relationship with the orientation of images in the other channel, the printed images are oriented randomly upside down when the read images are directly printed on a paper sheet without turning the images at every channel exchanging operations. It is a troublesome task to put the printed images in the normal orientation after the completion of printing operation. This poses a serious problem particularly when a number of images to be printed is designated by putting the corresponding codes into the memory through a keyboard and then the designated images are retrieved and printed automatically. Although it is possible to exchange the retrieved channel and to invert the orientation of the image by a manual operation, or to remove the microfilm roll from the reader/printer and then reload it in the upside-down condition by hand, such a manual operation is cumbersome and inefficient and cannot be adopted in an automated system in which a number of image codes is stored in a memory so that corresponding images are successively printed.